SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fb79ad61030309e881f60ea5af2579526882f2338039e3c8701056f0ad3f595' 
  AND token = 'eP1eVXdgh9Gy7w+ccjZHtFFklbb8QbeoKSRcvx570NY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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