SELECT 
  1 
FROM 
  tmall_lock_keys 
WHERE 
  key_id = '6c94b4235716642335e61d0e9685b871f250fadc5c1db5a76e6879cf9ddcc749' 
  AND token = 'WZ1C/U7ePf4pbi/pPf+jjN+hGAyDLjHwectoGPBM3wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00779

JSON explain

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