SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6ea300239a053ba42b90105cb59372a57ab52a96a62bec9c9bf0bca000c14a8' 
  AND token = 'taM0dJwwyG+1mNMq33zsfqYt4Dzt4T8YhhG/1k50KwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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