SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c7cd176c98cefdf03626253705f7e65154cfbed39e9d3568d7b9e11b7515849' 
  AND token = 'gDbNxNE0kYfskkv0UDqsZmVQDnLQg62tSee/1xkZTBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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