SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9df8abaae0580f10e0faa655d9acc0b096878bd7bd052f5d51ac6a5c96b81ad' 
  AND token = 'o42HdCZvYT44MjTvO2i5mEmZUe4g0+L3pXdL5AE1bJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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