SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd741b4f12462d8db7821469babc6ea1d9c4f65d1833e33af79155967775de033' 
  AND token = 'lKMc7K18twprJDINQ5fHWWPRWd3VHFhrLjDT6YrswtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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