SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a685f00525fb0b4b05b17c6a844ac1423fbe6ad2dce1ece9feac6cdf66c22b72' 
  AND token = 't8YUojBHm/us974dz5HCCwUuE/AIK412WEtu02CgHLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}