SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b036e4923caf7c76f417af6ab38f05ce75725aa993202ba0756afa6e1e34c9d5' 
  AND token = 'Xf/30gBAPAtEGC0GUwewlqiKQO8B1lqANH0z0AilKjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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