SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '929be6fc307be0631d2ace18876ed67ac1a1b378e904276762e765d814b87f7d' 
  AND token = 'iwMtisc8fQwA8nz+dV7WSIPCVIVvlKKF7ZjLV6TcsI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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