SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28bbd904a80723299494dd14bda0bb989865d810fb6bd66eaf06749ab84bbf2a' 
  AND token = 'eSpB2ELNdbVBEz6DsNj7ehQv/UvbBHMyJytDSS8JBOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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