SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38d3dbbd35f1b6265dd165135dd6d92e39d222f4188aeabe9b45d7e9407ef84e' 
  AND token = 'rMA4XtL1KhuiqhDfxjgdLwFmJHcuFEg92VgscZY/8EA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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