SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '088c4c21bc53443d5c99e483e7fb014960847f1c501f7f150b3f8165c2841274' 
  AND token = 'CHaRjvXIfjEYDU8h4GlDR+KGyTBZAnAmcPj5c/qWV4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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