SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d61e0dd42c4194d1758684f69055340cc1414b73808edcfaaf704b3bbb41c8b' 
  AND token = 'SrZ7Ki+/uW+7PYo+5MrtuOhKKOwv5pY0Xxjg5CbjQZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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