SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '140fe5af8e5a5603db7f8ba266c8b926a26a31a473678af92a81b6d04a6321bd' 
  AND token = 'QLPIuyQR2K5bEDutirtPI5pXvkU8U5rSnPUn88si7DU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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