SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10c3caa74eeaf04f5aae7c606462ea234307294b81b06a509943e95fe48ed7a5' 
  AND token = 'JhqlNVkPjakvi8xYNDMxKQzmpuyn8RwfspjqfKTzytk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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