SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b100a5a313240be0f68e318463c0e6b175468fa32adc2bc7447946ca2c65fb2' 
  AND token = 'ZZF+Xlz6oHVLpg4FAX5Y7Xm8FbpC/tpGy6BmjRAa9xM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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