SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e31f615173afa566305b120c6e185ca715c075aa7818816dd937a26be2f91944' 
  AND token = 'FTmqu7msxFex1Zz0QOcq1Wpt/VKGKF7M08pOZ8lC87o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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