SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38f2c53ab7462339a15a5ab9b75cbb0c16cef9361437dae265e67ac5472ceb0b' 
  AND token = 'IJw0VCSVvjYQFsT9gaCH7kbrMZtGEZz0VooVKEpFvdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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