SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50a192bd66ef7b02c4adbefcf1f20ed3d863e13f240da80914d3679125f4421a' 
  AND token = 'jy5myKa8hFNcO4ned2IsHAOwu8bs0Cohm3pvMUfHoyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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