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SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '409fc14c1101cf1e4d306a59cdf5af00fc1368a8cbdd0ce9ccf09f9c5870e829' 
  AND token = 'm7di3TDTsNj87LjYdhfBX4dL44M2AxPdch/jGEFv3sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00928

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}