SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2973e63c1f9c493683ca246ae146a0c3f22164427eef919b4afc5446233fc375' 
  AND token = '1HpYNr54WJUvTzO0wjEy4rkNCZChKf6wtvPiBWCB5vQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00073

JSON explain

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