SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68593eed3d4c151bfab749f83d0701c777af3115d261863fe536d20f889bddef' 
  AND token = 'Iqox0RMb279bkFH1AYWgL2j0z2z+JqojKjAvhp68m9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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