SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e850ca128ae468f8ae47638b3dec4c6bc73b5c4f97b338185f7ba426a5af19c' 
  AND token = '2Cg65ZurC+GkY4WMhzApJ9svP/S5+cqWwlZXx494Syw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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