SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89d9a7ae299981512ad437c89c9dc461eacb04259ecc8f99c279650030ee6a3f' 
  AND token = 'LJrCL7Qt49USjloa8ZSnH85LwcaVGMP624sQi7fxvW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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