SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af500fdc37de93d3ea3b0144585fc1a8502e48b3bf0fd69855800b2b60f3d0c0' 
  AND token = 'HDu8IxXvpLOz40WYVzZ+OAqXTxXWWLVQdqkdgufeB7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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