SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37aee8fa7ff17c196c515fea041c7569753a405fa1cb6a4bdbddf33cee4cf8cd' 
  AND token = 'gJYWU0ZrZ2r1dRUVTXicAtfPecisLufwJtREFjAA+cQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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