SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4adf9d7de67c9c97d56cee99da3508222e71ee059f2d47551f3f38202c6577d6' 
  AND token = 'jz5LMoAHVsQlrZohoIMEg8FijaMv7HIwZtj4VjCAFIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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