SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4866db17bd105aebf06d37ba4519ccc657baadbdfb12d2edf68f8ca94d2e555' 
  AND token = 'xvpvnv4NVhs2B4uyowJLhkbt3qp/ZjLSVBaXvWD4qyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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