SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '257b96d01b698f851589b6a922b72895d6fa6673afb84f9bcb97635003862b7f' 
  AND token = 'ymAgv2oUpaeJ6xgDgEIB7DQd0+PADzuGZq7uKYozzyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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