SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e84ba8c8f791bf201602a15ff0d635463091166fd85758a564f1b01989f26e7c' 
  AND token = 'ifZEYqgux+RCkgMeJNgL02O5Sqkg2oa16DF1FMoAGIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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