SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4765a9c6b9adb7141c9eccc35ef9ea5ddb06429dc571216ce873b8af3230e2d6' 
  AND token = '71Lj7ZzBn+BbYAWNFCCphqeoEu5ixIGleM1oQKqpPhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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