SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b7a278da5c2da3bf7815cfa6cbb558594cc3991307b02795be8235b87583c48' 
  AND token = 'Tpln05UAiyOg3psiCdnWIUt8DTD8ZaotlMRNtyCqwNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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