SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a15f4c507603b70bb4a04a06ca46f74915f715c109fd82e6bc13ea4a1d97bbb' 
  AND token = 'F2JzluUgAJNHLB9YZTiB5SnIZr/yue+FE/RHtl+OPL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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