SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '196fda1b177372950d7180e16c757eafd5cd106789a02fee2f7bf7a0bf936fb4' 
  AND token = '7DlpTF0w8pJdashWK1S9hgQYDuzXT/ZS+D6hRSVHHqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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