SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af2c29933ab8cdc76d86b180fb0bffeceaf8f3367a9bd2ab936fb4a76a8c7126' 
  AND token = 'si5qwDZOTikS6fXRRwOPEBC2Z+RR13OxcJw6CBjrTcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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