SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba6c6fcf6fc74fcba50883e9cc44f9cd6137d76cd7dd392e5dee27e4e08c34c8' 
  AND token = 'dbSH6mBMQRZ0zuQOh1nC5Z53EcQmWLZjfkRI0EiAgtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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