SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1a52216446384b511562e7a96e1ec110cb2b6ad02c77af1e77015a5569c5ecf' 
  AND token = 'YXk1onGxe7UHJgYSjp5ktqKMQYeQKimH3NARXmKU0xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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