SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81fad5d567c0e842e0b0e166aaa30328da02cfb2751c37a1da3329e0bc8edd55' 
  AND token = 'CvDBDawQ8uOJBL2j99jo/10NhLkShUH0fcWcPwtF4Pk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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