SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82c50191252f2ab1f840946201d45d6b75b79861636101e16b765b57cabf4466' 
  AND token = 'xAnDL2/INuNtxt/W3JlohqUELqwmMnkIZvfeTJz+vKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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