SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1cd63587642e2e705ad65130025c9a584d069ea398b16bf1e1bcbf1b609ea39' 
  AND token = '7ckbOQdvpUWoGfIey6BhUsnyaDA8zaXOsCXAEWS/sEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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