SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c8e2823c71a93fa2d9b7da907ef743fd292807e48c6a56663bacff45ba0260d' 
  AND token = 'QLg6CGgjCiILQuQT6+eA7ZM/Bh+csm2vbucWn9lUgv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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