SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47a2ee0f79c9276ce496b02224498faff806ede885014aab086685e07ad8fa22' 
  AND token = 'xz8GyKyBoUwdMUd/smIsFwMVXO1rCa6u3y3tiOs5C8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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