SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '719bced0354b0def8e193aebef866cb5bb0376928fdcd11ce0025ba32b5bc6e9' 
  AND token = 'RdVCzi4lccxH5A0I7V//mmhS+jt0Q/XnclcFUx94LhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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