SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'facd846bcea9f5805dccbef69da3a057ba89354390971fa866aed8ae1d51362a' 
  AND token = 'hW0lsXRgfYgH5AUrQefQdPA6rQVMcZ0kJq7dqAHorcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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