SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c090576a7ecfcaf88b9f3b83e62e0b831b0d2bc611f17d8ec644356d42519fe0' 
  AND token = 'QOVACGNMpFyJbn/s6G9RujZMvks0hgbrTJgeYCkbwWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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