SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc365a8d16dd7701988a20c3da3bfb9a97b4cc9e6da07b26d0a34326ae2996b0' 
  AND token = 'HPHnIBDp450E5HdZWdch6MRKlMO88yA9o/HEaJ7EnO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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