SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9871edee82d60de6b68322e307134fb03c58df4212a31ef19fae945b1fd4f7e8' 
  AND token = 'jAYUW+hqK8ftZwFy+rhEuKINYciwaFjLGzZ0Oy5WCek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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