SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14d8b3657d4dd8a6efe75c12ecf11d5cbb9c3509d5b92a6419bbca19eff2a7a5' 
  AND token = 'UVtpD/rMZZHyEwrY6bKJZIgmKZdIk1a5DweBlR+VHWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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