SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34e7d76b09d313c219d28db447c41a8588d586579f3887610ac2aa3536c46ced' 
  AND token = '4YVCbCcakcfIh1uiJJEBxNUqgvzjtJISPKv4ISOYs3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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