SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03536a11b44bdda40cf7cebd17105d52accb1fcf17ec0a5d8e91fd02d985acea' 
  AND token = '/duk+XyUceRDmesRHyHj4yUfBL5pmtkOJAw91I0KgJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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