SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d7fcb4cf424db65930499ebc950008feb56f6dd9adf85f88bedbb6ef208f0d4' 
  AND token = 'MJlSbKrBdLRodoDmlb9g8lbfFM09v6YOzoCT6GJ4wDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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