SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55a974c97e8d66df27f5fcd0c677c3104fc39eb8a130012ca58ed57dd761c120' 
  AND token = 'KytCdx0zPNp+LYv5K1Bxl7eyw4kpkw7qnR1TZhteHk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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