SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c98fcccb39248f3f103736168f994809fd6ad458ff3b7054db6840724fc24798' 
  AND token = 'zIpXQgHGqsaZpOYCIl/p5XSwCrdlharSbxg6BUTAeDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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