SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78b5ae24012e3478d5bf86c406556aa3b9261f4be30e806feb68375d0f314529' 
  AND token = 'hiwgmMZI+BnPFVfnXHOWmpzlnvkOQdm3i8KJANEjqA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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