SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc771523b9c82d31642ec7920974816abdc66155755eb0aa327975195119a8de' 
  AND token = 'UlU5taCiYsBs2v8pX4JiBturBL2aek/JxZEUrlorG00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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