SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ad652b71108a83a4c13e887e3a71072ef09645d0f712de14fcd76a209b39654' 
  AND token = 'xvBvfjyJIvEYNz8cz2JNp6wFaCnwx+pINPXSrERYtdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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