SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac8faa2b473676da8422fcffc530a6e78a2ab2b17a87d33922013ff4c03680cb' 
  AND token = '4PKfNBuDmLomErQHtWKDaZGUzQp/OE0xVCt5GeAzZA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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