SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50f93f06c3021829eb7f72bb3cda07d8d2f0de2aa4601055df05264d11f95ba3' 
  AND token = 'KHBkvxL3CbPEOGFiHEm94M820YLkPiqE9Ou869IyTQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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