SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8a35b6bbaa2d30954dcf10dadcbabe97fa56899ad4c635ec644ba4a8f440f80' 
  AND token = '2Dq8mvIgr2fAZrOsDV4zr15qqqEUr8V+pCPn9AENBd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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