SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a4734f2f3cdb2e3f4bf1146ee9abb9b75fabd35b964486dbda4069a431d916c' 
  AND token = 'gzJBht1VDoHYtNhdlOrNlWylfWKnQ+QZFmnI7LiWZVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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