SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93b46b60b7d242a6577c0f1e57a13e29a9b545edcf988e36a3d586a92d44789c' 
  AND token = 'Ui/I2Y9/wydfH57ASGld/BUThrl4UKmzEmYPwCg3XhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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