SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f91ec401732335c2baff0247070a3e4e561abb19e8e8184f7b6468d02774586e' 
  AND token = 'x6AscvGT7pfXcFb55lZUQGVLHqIsRgSKrskGla7Yg7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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