SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8a3da0eb1c0275901a554f32d2569c58cea309bed77f4f67d3a79871898021b' 
  AND token = 'ZGI4OvhymUSMulr8Ym6vrST9Gf6Cq0LK+fyscvs7hJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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