SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac45bd3030a39c721a006c9042453f6077245bd0d9870e4205f9f982a7e04836' 
  AND token = 'iCXXjMWyNq/OUcxI/rC9HW+9KBC6AMiiwxdlY6y/gFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}