SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d5db69c0320d9c85c0ac9045df7bee71187342390a3d2031da5c4838e101377' 
  AND token = '2/QVyhR4YqQzOAbec8PZvs/JNHmQlVa3uwBpK5CEEvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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