SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78844a840b24484836ab5d9e8bfa560fcdd0baeb27040257243507599db8fe7f' 
  AND token = 'iDXjtMvcwFNkGEvVu8rKblr2T96eRuS6wfHhoPxvPWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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