SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd81759cd58d187e25d8749e72cb2ec84dd2ca6f8ce41e7c2da46fb2369fd99ff' 
  AND token = 'A/jq7iKHnUj4IqzScskwVlgiDqDM0prca0f38arnGp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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