SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a154d6e397664e064a8b5a8fbf3c7eb031dabfd3ae5ccd1d90c6f7da72408bd6' 
  AND token = 'Qbn1ffGnSjHVSQPkJNqv+PHOdjzzqabUHKUP0Lqa3gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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