SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3418f56d94b75656e041249d865db9280f1cc6d5edc42aa159b03986ab02c37c' 
  AND token = 'r4ugbFs9zinSb3D4gjDAP67FfhBJFOZagKF9768J6c0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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