SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c76c7931d4ee4f84d9f5e63d5c667323a74786202bed193962c181ce3c33c81' 
  AND token = 'WeqeiR4BTZklmYnuFhqQ9ZkPl33sG8bdpm70glokjwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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