SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e45bdf27c059ac770cbb0d2b45a1b795c7593c0943b401d6c91f2597d08b418' 
  AND token = 'cxmphqccoVEeF8WbfJdYuoUidP/ATstsS3RwiizgKR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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