SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21fa733924d30627b828c16a2f8a13a16a08ac52600919a46116eb6bed806ef1' 
  AND token = 'P3hLEF+LtQbBvIqGp5jtb/ifCOzgabHpt6wn2LzBAVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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